UPDATE: The video has been removed. The description of the scene is in the original article below.
A Spider-Man: Homecoming deleted scene confirms that Miles Morales, the Ultimate version of the web-slinger, exists in the Marvel Cinematic Universe. While Homecoming was ostensibly the proper introduction of Spidey into the MCU, showing how Peter Parker works in a world of Iron Men for the first time on the big screen, it was also setting up his replacement.
Since he was introduced in 2011, Miles Morales - the Afro-Latino successor to Peter Parker - has become a firm fan favorite, and one many have been hoping to eventually see on the big screen. This was teased in Homecoming with Aaron Davis, Donald Glover's small-time criminal who, in addition to going being a burglar by the alias the Prowler, is Miles' uncle in the comics; during his meeting with an interrogator-mode Spidey the film, Davis mentioned wanting to protect his nephew. That alluded to Morales' existence - a reference later confirmed by Kevin Feige - but now we have explicit proof.
A deleted scene from the upcoming home video release of Homecoming has emerged online. In what appears to be an alternate post-credits scene, we see Davis still webbed to his car after his run-in with Spider-Man earlier in the film. He struggles to escape and eventually rings his nephew to say he won't make it to see him, calling the kid Miles.
In the Ultimate Marvel Universe, Miles was a regular teenager given powers by a radioactive spider replicated from Peter Parker's blood and stolen by his uncle. After the death of Parker, he took up the Spider-Man mantle proper, and due to his immense popularity with readers eventually became a part of the main 616-universe. At present, he is New York's main Spider-Man, with a living Peter taking on global duties.
Morales coming over the MCU is thus a major deal. Of course, the reveal in this deleted scene was heavily alluded to in the movie itself and taken as fact by many, but hearing Davis actually say Miles means a lot. Indeed, it's a big shame this scene was cut - presumably it was replaced by the Captain America PSA, which while admittedly was funnier has less far-reaching impact.
With Glover's role setting up Miles' origin and it clear the filmmakers want him to have a presence, the question now becomes whether he'll make an appearance in Spider-Man: Homecoming 2. That would seem plausible given it's the current end-point of the publicly discussed Peter Parker MCU arc and Tom Holland himself has discussed mentoring a new actor, although considering Miles' origins obviously poses its own, deadly issues.
Whenever Morales does appear in live-action, it will likely be after his real big screen debut; he'll be the subject of 2018's animated Spider-Man film, which features the voices of Shameik Moore as Miles and Mahershala Ali as Davis. And before that, he'll have a role to play in the PS4 Spider-Man game.